Various anticholinergic compounds have been previously described but are not optimal.
Muscarinic receptor antagonists are frequently used therapeutic agents that inhibit the effects of acetylcholine by blocking its binding to muscarinic cholinergic receptors at neuroeffector sites on smooth muscle, cardiac muscle, and gland cells as well as in peripheral ganglia and in the central nervous system (CNS). However, their side effects, which can include dry mouth, photophobia, blurred vision, urinary hesitancy and retention, drowsiness, dizziness, restlessness, irritability, disorientation, hallucinations, tachycardia and cardiac arrhythmias, nausea, constipation, and severe allergic reactions, often limit their clinical use. Topical administration of anticholinergic agents to targeted areas, such as sweat glands, where the localized blockage of muscarinic receptors will be of clinical benefit would be a desirable therapeutic strategy. However currently used topical anticholinergics can exhibit unwanted systemic side effects which can limit the dosage that can be safely administered.
Glycopyrrolate is among the quaternary ammonium anticholinergics which have reduced CNS-related side effects as they cannot cross the blood-brain barrier; however, because glycopyrrolate is eliminated mainly as unchanged drug or active metabolite, its topical administration is often associated with common undesirable anticholinergic systemic side effects. To increase the therapeutic index of anticholinergics, the soft drug approach has been applied in a number of different designs starting from various lead compounds, but there is a need for yet other new soft anticholinergics with clinically meaningful biological activity. These novel muscarinic antagonists, just as all other soft drugs, are designed to elicit their intended pharmacological effect at the site of application, but to be quickly metabolized into their designed-in, inactive metabolite upon entering the systemic circulation and rapidly eliminated from the body, resulting in reduced systemic side effects and increased therapeutic index.
Soft anticholinergic zwitterions have been described in US Publication No. 2012/0141401, and its related patents, U.S. Pat. Nos. 8,071,693; 7,538,219; and 7,417,147. Soft anticholinergic esters have been described in US Publication No. 2012/0177590 and its related U.S. Pat. Nos. 8,147,809; 7,576,210; and 7,399,861. Although these published applications and patents identified the potential for the zwitterion or ester forms of anticholinergics to be used for treating hyperhidrosis, activity and duration of action are unexpectedly high, based on a comparison to published mydriasis data, was not known or previously described.
Each of the US Publication Nos. 2012/0141401 and 2012/0177590 and their related U.S. Pat. No. 8,147,809; U.S. Pat. Nos. 8,071,693; 7,576,210; 7,538,219; 7,417,147; and 7,399,861 are hereby incorporated by reference in their entirety.
Hyperhidrosis is an idiopathic pathological condition characterized by excessive, uncontrollable sweating beyond that required to cool the body. A hyperfunction of the sweat glands and a disturbance of their cholinergic stimulation have been described as possible causes of this condition. It is known to affect approximately 3% of the population. Hyperhidrosis not only may result in intense social embarrassment, but also may even interfere with a person's occupation.
Hyperhidrosis most often involves one or several areas, especially the hands, axillae, feet or face, although it can even involve the whole body. Axillary hyperhidrosis is the most common form, followed by palmar hyperhidrosis. Antiperspirants alone are generally not effective in treating this excessive perspiration. Oral medications are occasionally beneficial, but may have side effects. Other therapeutic alternatives include surgical procedure such endoscopic thoracic sympathectomy. Although the surgery affords permanent benefit in some 40% to 90% of affected individuals, it is invasive, requires general anesthesia and is not without potential side effects. As many as 50% of persons who have undergone thoracic sympathectomy develop compensatory and annoying sweating of the trunk or thighs.
Botulinum A neurotoxin (BOTOX) which blocks the action on sweat glands of acetylcholine that is released by the autonomic nerves, has proven effective in hyperhidrosis. Minute amounts of BOTOX injected into the palms or axillae of affected individuals results in statistically significant benefit. The effect lasts for several months but requires repeated injections and is often not a suitable alternative for pediatric patients.
A non-invasive, convenient and effective treatment having high sweat reduction activity, long duration, and with fewer side effects would be a welcome alternative for treating hyperhidrosis.
Topical glycopyrrolate has been used previously to treat gustatory sweating associated with diabetic autonomic neuropathy. In this disorder, sweating that often is profuse, begins soon after the patient ingests food, starting on the forehead and then involving the face, scalp and neck. A solution of glycopyrrolate was applied to the face of the patient which prevented the gustatory sweating.
Similarly, glycopyrrolate has also been used previously to treat gustatory sweating associated with Frey's syndrome which may develop after parotidectomy. Frey's syndrome is believed to result from the aberrant re-innervation of the sweat glands of the face by the severed parotid parasympathetic nerve fibers.
In both diabetic gustatory sweating and Frey's syndrome, the profuse facial sweating is induced by the specific stimulus of eating. Moreover, the sweating in each is a consequence of a distinct neuropathological process. In contrast, hyperhidrosis occurs spontaneously without a specific stimulus.
This application is directed in part to the discovery that the daily topical application of a 5% concentration of a soft-anticholinergic compound to a mammal overcomes many of the prior problems in treating hyperhidrosis. In previous published mydriatic studies comparing soft-anticholinergic compounds to glycopyrrolate, comparable activity appears to have required as much as five times (5×) or more the concentration of the soft-anticholinergic compounds compared to glycopyrrolate. Surprisingly a compound as defined herein can provide clinically significant reduction of sweat production at a level of similar sweat reduction reported using comparable doses of glycopyrrolate, potentially making it a suitable treatment alternative for hyperhidrosis.
Additionally, there are provided advantages heretofore not achieved by conventional treatments for hyperhidrosis. For example, the soft-anticholinergic compound to be applied does not have the side effects associated with Botox treatments and may have an improved safety profile when compared to the systemic anticholinergic agents or topical glycopyrrolate.